Heat the oven to 350°F. Line a 9-inch square baking dish with aluminum foil or parchment paper so that it goes up all 4 sides.

Melt 1 stick salted butter in a small saucepan over medium heat, then continue cooking until it boils and turns a light golden color, 3 to 5 minutes. There will be some toasty milk solids that settle in the pan, they’re a good thing. Add ½ cup pakced brown sugar, 1 cup plus 2 tablespoons all-purpose flour, and a generous pinch of salt. Mix with a wooden spoon until a thick ball of dough develops.

Transfer the dough to the baking pan and use the spoon to press it into a rough, even layer. Cover with plastic wrap and use your hands to press and smooth the dough out. Remove the plastic wrap.

Bake until the crust is golden brown, about 20 minutes. Place on a wire rack to cool while you make the filling.

Stir 1 (14-ounce) can sweetened condensed milk, ¼ cup maple syrup, 1 large egg white, 1 tablespoon vanilla extract, 1 teaspoon pumpkin pie spice, and ¼ teaspoon salt together in a medium bowl. Sprinkle 2 cups flaked, sweetened coconut over the crust. Sprinkle 1 cup finely chopped chocolate or mini chocolate chips and 1 cup toasted pecans over the coconut. Pour the maple mixture evenlly over the top.

Bake until the top is golden brown, 30 to 35 minutes. Let cool slightly before grasping the foil or parchment and removing the slab from the pan to a wire rack. Let cool completely before cutting into 16 bars.